As for this kind of automatic fire extinguishing device, the automatic fire extinguishing device of direct system and the automatic fire extinguishing device of indirect system are known. As shown in FIG. 5, the automatic fire extinguishing device of direct system is comprised of the pressure resistant container 10 filled with extinguishant and pressurization agent, the container valve 12 attached to the opening of the pressure resistant container 10 and fire detection tube 14 connected to the container valve 12.
As shown in FIG. 6, the automatic fire extinguishing device of indirect system is comprised of the pressure resistant container 10 filled with extinguishant and pressurization agent, the container valve 12 attached to the opening of the pressure resistant container 10, the fire detection tube 14 connected to the container valve 12 and the jet nozzle 26 connected through the extinguishant supplying tube 24 to the container valve 12.
As materials of the fire detection tube 14, the synthetic resin, e.g. polyamide resin, is used. Because if the synthetic resin is used as the materials, the pressurization agent is hard to leak out from the tube and in case of a fire the tube becomes weak due to the heat of the fire and the weakened part is ruptured by the pressure of the pressurization agent and a hole would be open.
These automatic fire extinguishing devices are installed in a fire dangerous area (where there is a risk of a fire) such as a wind-power generator, an escalator machine room, a switchboard, a distribution board, a transformer, the engine room of the car, the engine room of the ship, the engine room of the heavy industrial machine for the construction. And the fire detection tube 14 of the automatic fire extinguishing device is installed in the meander condition in this device.
As explained next, these automatic fire extinguishing devices are able to detect the fire and extinguish the fire automatically.
In other words, when a fire breaks out in somewhere in the fire dangerous area, the fire detection tube 14 becomes weak by the heat of the fire, and this weakened part is ruptured by the pressure of the pressurization agent, and a hole is open on the fire detection tube 14, and the pressurization agent in the fire detection tube 14 is jetted out, and the pressure in the fire detection tube 14 becomes low.
In case of the fire extinguishing device of the direct system, the inside of the pressure resistant container 10 is communicated with the inside of the fire detection tube 14 each other by the container valve 12. When the inside pressure of the fire detection tube 14 becomes low, the fire extinguishant inside of the pressure resistant container 10 is supplied to a hole of the fire detection tube. Then the fire extinguishant is jetted out from the hole on the fire detection tube with the pressurization agent and the fire is put out by the extinguishant which is jetted out to the source of the fire.
In case of the automatic fire extinguishing device of the indirect system, the injection nozzle 26 is connected to the container valve 12 through the extinguishant tube 24 which is a different system of the fire detection tube 14, when the inside pressure of the fire detection tube 14 becomes low, the container valve 12 which supplies the extinguishant to the injection nozzle 26 is open. The extinguishant inside of the pressure resistant container is supplied to the injection nozzle 26 by the pressurization agent. The fire is put out by the extinguishant which is jetted out to the source of the fire with the pressurization agent from the injection nozzle 26.
These automatic fire extinguishing devices would not produce electric sparks during fire detecting operations because they do not use electricity to detect and extinguish a fire. Therefore, when these automatic fire extinguishing devices are installed in the place surrounded by many flammable gas and dust, there is no worrying factor of explosion by catching a fire on the flammable gas or dust. Thus, there is the advantage that these automatic fire extinguishing devices can be used safely even in the explosion proof area.
In addition, these automatic fire extinguishing devices do not detect the occurrence of a fire optically. And they detect the fire by a hole opening on the synthetic resin fire detection tube by the heat of the fire. Therefore, even if the fire detection tube working as a sensor becomes dirty with long-term setting, there is an advantage that the fire detection function of these automatic fire extinguishing devices would not deteriorate and there is no fear that they do not function properly.
In addition, this automatic fire extinguishing device does not use a sensor nor a control unit using the electricity and the fire detection tube becomes the sensor and the fire extinguishant would be carried to the source of the fire automatically. Therefore these automatic fire extinguishing devices have the advantages of extinguishing the fire immediately even in case of the power supply loss caused by the blackouts and so on.
In addition, a battery is not necessary as a power supply because this automatic fire extinguishing device does not use a sensor and a control unit which is operated by the electricity, and thus also there is no need of exchange of batteries or any need of maintenance. Therefore, this automatic fire extinguishing device has the advantage of not worrying about the function stop of the sensor and control unit due to the natural discharge of the battery while installed for a long term.
This kind of automatic fire extinguishing device has various advantages as mentioned above. However, the fire detection tube used in this kind of the automatic fire extinguishing device is made of synthetic resin. Therefore, this fire detection tube is not able to shut off the leakage of the pressurization agent completely such as nitrogen gas and when this device is installed for a long term, the pressure agent leaks by penetrating through the fire detection tube and the pressure of the pressure container and the pressure inside of the fire detection tube becomes low.
When the pressure of the pressure container and inside of the fire detection tube reduces, in case of a fire, the extinguishant might not be able to be jetted out with enough force. Therefore, the pressure of the pressure container and inside of the fire detection tube should be checked in every fixed period of time, and if the reduction of the pressure is remarkable, the pressurization agent must be replenished to inside of the pressure container. However, the automatic fire extinguishing device tends to be installed in the place difficult to access and in the small place, it is very troublesome to perform the maintenance of automatic fire extinguishing device in such a place frequently.
Therefore it is desirable that the fire detection tube in which the pressurization gas hardly leaks for a long term such as 5 to 10 years and also that it has a characteristic of being ruptured easily by the heat of the fire.